1. Field of the Invention
The invention relates to the fabrication of integrated circuit devices, and more particularly, to a method of removing particles contaminating the surface of integrated circuit devices.
2. Description of the Prior Art
Defect reduction is one of the major issues for the fabrication of high-yield very large scale integrated circuit (VLSI) devices with feature sizes in the sub-micrometer range. Many cleaning processes, including wet chemical and vapor dry etching, have been adopted in the fabrication to reduce particles on wafers. However, no process has been able to clean wafers to be particle-free up to now.
The sources of particles on wafers are the ambient, the wafer holder, chemical solutions, de-ionized water, other wafer cross-contamination, machines, process reactions, etc. Most of the particles are attracted to the wafer surface by means of van der Waal's forces or by adsorption. If these particles remain on the wafer surface, it is difficult to remove them after films are deposited thereon.
A number of patents have addressed the unwanted particle issue. U.S. Pat. No. 5,164,093 to Chilton et al describes a method and a device for removing particles from circulating fluids, which fluids are then used to clean the wafer. U.S. Pat. No. 5,151,135 to Magee et al uses short, low-energy pulses of ultraviolet laser radiation to break bonds and to fragment and vaporize particles on the wafer's surface. U.S. Pat. No. 5,024,968 to Engelsberg teaches pulsed laser irradiation during inert gas flow to clean surfaces of contaminants.